Enable H.264 temporal scalability in simulcast.

Bug: webrtc:10651
Change-Id: I58372186930ce33e925f85edb0f308657dbfe273
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/142840
Reviewed-by: Sergey Silkin <ssilkin@webrtc.org>
Reviewed-by: Stefan Holmer <stefan@webrtc.org>
Commit-Queue: Sergey Silkin <ssilkin@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#28381}

modules/video_coding/codecs/h264/h264_simulcast_unittest.cc

@@ -95,5 +95,10 @@ TEST(TestH264Simulcast, TestStrideEncodeDecode) {
   fixture->TestStrideEncodeDecode();
 }
 
+TEST(TestH264Simulcast, TestSpatioTemporalLayers333PatternEncoder) {
+  auto fixture = CreateSpecificSimulcastTestFixture();
+  fixture->TestSpatioTemporalLayers333PatternEncoder();
+}
+
 }  // namespace test
 }  // namespace webrtc